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Audio Advertising Specifications
General recommendations for audio creative are below. While these requirements will enable delivery across most inventory sources, specifications vary by publisher and SSP — the Geaux Grow team can confirm publisher-specific requirements for your campaign.
| Specification | General Recommendation |
|---|---|
| File type | MP3, M4A, WAV (OGG files are supported in third-party tags) |
| File Size | Max 500 MB |
| Spot Length | 15 and/or 30 seconds (we recommend both for maximum reach and scale) |
| Bitrate | Minimum 160 kbps, max 320 kbps. Hosted MP3 files must have a constant bitrate, not variable. If running on a specific publisher, refer to publisher-specific requirements. |
| Script Word Count | Up to 65 words if running on Spotify, or refer to publisher-specific requirements |
| VAST Version (for 3rd-party tags) | VAST 2.0 is most widely supported across all audio publishers |
| Companion Banner | 300x250, static JPEG, 50KB max for general inventory (otherwise refer to publisher-specific requirements). Delivery is not guaranteed but recommended. If using third-party tags, companion banners should be contained within the tag. |
Audio Creative Best Practices
- Make sure your ad length is ideal. For music streaming, the ideal length is 15 or 30 seconds. For podcasts, longer ads (35+ seconds) have been found to drive better results.
- Repeat the brand name within the first five seconds. Saying the brand name early and often helps the listener remember it.
- Repeat the call to action. Repeating the CTA two or more times helps drive engagement.
- State any URLs clearly. Make sure URLs are easy to read aloud without special characters like slashes or dashes, and spell them out if needed.
- Incorporate sonic branding. Include a sound listeners can immediately recognize and connect to the brand — the same intro used across ads, a jingle, or a character voice.
- Make sure speech mirrors natural conversation. Use relatable language with a conversational tone.
- Focus on one memorable message. Share information clearly and directly, and avoid cramming multiple messages into a single ad.
- Avoid crammed or rushed ads. Aim for a script of 60–65 words for a 30-second spot, with a deliberate cadence and well-timed pauses.